/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.util;

import proguard.classfile.*;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.visitor.ClassVisitor;

/**
 * This ClassVisitor initializes the superclass hierarchy of all classes that it visits.
 * <p>
 * Visited library classes get direct references to their superclasses and interfaces, replacing the superclass names
 * and interface names. The direct references are equivalent to the names, but they are more efficient to work with.
 * <p>
 * This visitor optionally prints warnings if some superclasses can't be found or if they are in the program class pool.
 *
 * @author Eric Lafortune
 */
public class ClassSuperHierarchyInitializer extends SimplifiedVisitor implements ClassVisitor, ConstantVisitor {
    private final ClassPool programClassPool;
    private final ClassPool libraryClassPool;
    private final WarningPrinter missingWarningPrinter;
    private final WarningPrinter dependencyWarningPrinter;

    /**
     * Creates a new ClassSuperHierarchyInitializer that initializes the super hierarchy of all visited class files.
     */
    public ClassSuperHierarchyInitializer(ClassPool programClassPool, ClassPool libraryClassPool) {
        this(programClassPool, libraryClassPool, null, null);
    }

    /**
     * Creates a new ClassSuperHierarchyInitializer that initializes the super hierarchy of all visited class files,
     * optionally printing warnings if some classes can't be found or if they are in the program class pool.
     */
    public ClassSuperHierarchyInitializer(ClassPool programClassPool, ClassPool libraryClassPool,
        WarningPrinter missingWarningPrinter, WarningPrinter dependencyWarningPrinter) {
        this.programClassPool = programClassPool;
        this.libraryClassPool = libraryClassPool;
        this.missingWarningPrinter = missingWarningPrinter;
        this.dependencyWarningPrinter = dependencyWarningPrinter;
    }

    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass) {
        // Link to the super class.
        programClass.superClassConstantAccept(this);

        // Link to the interfaces.
        programClass.interfaceConstantsAccept(this);
    }

    public void visitLibraryClass(LibraryClass libraryClass) {
        String className = libraryClass.getName();

        // Link to the super class.
        String superClassName = libraryClass.superClassName;
        if (superClassName != null) {
            // Keep a reference to the superclass.
            libraryClass.superClass = findClass(className, superClassName);
        }

        // Link to the interfaces.
        if (libraryClass.interfaceNames != null) {
            String[] interfaceNames = libraryClass.interfaceNames;
            Clazz[] interfaceClasses = new Clazz[interfaceNames.length];

            for (int index = 0; index < interfaceNames.length; index++) {
                // Keep a reference to the interface class.
                interfaceClasses[index] = findClass(className, interfaceNames[index]);
            }

            libraryClass.interfaceClasses = interfaceClasses;
        }
    }

    // Implementations for ConstantVisitor.

    public void visitClassConstant(Clazz clazz, ClassConstant classConstant) {
        classConstant.referencedClass = findClass(clazz.getName(), classConstant.getName(clazz));
    }

    // Small utility methods.

    /**
     * Returns the class with the given name, either for the program class pool or from the library class pool, or
     * <code>null</code> if it can't be found.
     */
    private Clazz findClass(String referencingClassName, String name) {
        // First look for the class in the program class pool.
        Clazz clazz = programClassPool.getClass(name);

        // Otherwise look for the class in the library class pool.
        if (clazz == null) {
            clazz = libraryClassPool.getClass(name);

            if (clazz == null && missingWarningPrinter != null) {
                // We didn't find the superclass or interface. Print a warning.
                missingWarningPrinter.print(referencingClassName, name,
                    "Warning: " + ClassUtil.externalClassName(referencingClassName)
                        + ": can't find superclass or interface " + ClassUtil.externalClassName(name));
            }
        } else if (dependencyWarningPrinter != null) {
            // The superclass or interface was found in the program class pool.
            // Print a warning.
            dependencyWarningPrinter.print(referencingClassName, name,
                "Warning: library class " + ClassUtil.externalClassName(referencingClassName)
                    + " extends or implements program class " + ClassUtil.externalClassName(name));
        }

        return clazz;
    }
}
